It's true, I don't understand why units can jump on some trucks but not on cars. But the fence problem is a little different because the fence doesn't even occupy any area tiles, its between two tiles. It makes no sense that the units can't jump over it.

MFD is still one of the best gene mods though. I try give it to all units, especially the ones who don't have grappling hooks or jet armors. The combo of MFD + HnR on scouts / CE assault lets me get ahead in the campaign by farming large UFOs. It's fortunate that MFD shares the same slot as Adaptive Bone Marrow, which happens to be the least useful mods of all, so it's an easy choice.

Well, on the programming/game design field it is not that simple. Try to imagine: I understand that there is a function that allows moving to another tile IF it is 'on the same level' AND there is no wall between tiles. It denies the move otherwise. MFD removes the restriction of 'same level' but not the restriction of 'no wall'. Dot. That simple.If MFD removed 'no wall' restriction you would be probably able to walk through building walls. I know that when you see a 'small fence' that is 'small fence' for you. But in terms of game design that is 'a wall' with 'small fence' texture. Same as big building wall which is not one wall - these are several 'walls' on diferent levels with 'building wall' texture each.

So, in order to allow jumps over fences a designer faces several additional problems:1. a function to meseaure height of 'wall' by checking how many walls are there one above another2. a function to check jump availability - no roof/floor/obstacle above the head of a soldier, but conditional - roof allowed if higher than height of the wall, gee...3. additional animation4. referring to 1. a new problem arises. If there is a big wall (3 levels) with a hole made by grenade/rocket on second level (or just a window), but with wall on 3rd level: what is the height of wall? So - another function.... and so on

actually, these things are already in the game. You don't need additional functions to measure height of walls, the game already has that information. How do you think the game determines line of sight if it didn't know how high a barrier is? Also, "jump availability" is no different than "flight availability" which is already in the game. There are obstacles at different heights that prevent you from flying your units everywhere. If the game can 'calculate' where you can fly around, then it can be programmed to determine which barriers you can hop over.

I think modern games have much more complex physics than the things you say are difficult to implement.